---
id: CVE-2026-123588
title: >-
  Hickory DNS Recursive Resolver Denial of Service via Cached Empty Connection
  Pool
summary: >-
  The recursive resolver in Hickory DNS (all versions of the hickory-recursor
  crate, and hickory-resolver 0.26.0 before 0.26.2) caches an empty connection
  pool when it follows a referral with no glue records and all queries for the
  name se…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-754
vendor: hickory-dns
product: hickory-dns
affected:
  - hickory-dns <= 0.26.0-alpha.1
  - hickory-dns >= 0.26.0 < 0.26.2
published: '2026-11-08'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T01:38:20.288Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-123588'
references:
  - url: >-
      https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-9px7-7m25-f6q2
    label: GitHub Security Advisory (GHSA-9px7-7m25-f6q2)
  - url: >-
      https://www.vulncheck.com/advisories/hickory-dns-recursive-resolver-denial-of-service-via-cached-empty-connection-pool
    label: >-
      VulnCheck Advisory: Hickory DNS Recursive Resolver Denial of Service via
      Cached Empty Connection Pool
tags:
  - cve.org
ingestedAt: '2026-11-08T02:43:18.650Z'
---

## Overview

The recursive resolver in Hickory DNS (all versions of the hickory-recursor crate, and hickory-resolver 0.26.0 before 0.26.2) caches an empty connection pool when it follows a referral with no glue records and all queries for the name servers' IP addresses fail. An attacker able to spoof DNS responses can make these lookups fail, causing all subsequent queries for the affected zone to fail until the cache entry expires or is evicted.

## Affected

- `hickory-dns <= 0.26.0-alpha.1`
- `hickory-dns >= 0.26.0 < 0.26.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.